The present invention relates to ultrasound imaging with reduced speckle. In particular, ultrasound data associated with different spatial and/or frequency content is compounded. Speckle information in one frame of data is decorrelated with speckle information in another frame of data associated with different spatial or frequency content. By compounding the frames of data, the decorrelated speckle is reduced.
U.S. pat. No. 6,511,426 (U.S. application Ser. No. 09/328,113) shows reducing speckle through elevation compounding. Frames of data from scan planes having different elevation positions are compounded together. For example, the transducer is translated along the elevation dimension or an elevation aperture is translated in the elevation dimension along a multi-dimensional transducer array. The compounded frames have reduced speckle variation.
U.S. pat. No. 5,653,235 discloses a system for reducing speckle for two-dimensional imaging. A two-dimensional transducer array produces multiple beams at different orientations. A scan plane is rotated to insonify a particular location from different angles. The data for the spatial location is compounded.
Multi-dimensional transducer arrays are also used for imaging without compounding. For example, 1.25D, 1.5D or 1.75D arrays are used to acquire data representing a scan plane. Rows of elements along the elevation dimension are used to electronically or mechanically focus the transmitted energy in the elevation dimension, increasing resolution.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiments described below include methods and systems for reducing speckle using compounding with multi-dimensional transducer arrays. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data representing a same scan plane, but with different elevational spatial frequency content. The elevation aperture for one frame of data is different than an elevation aperture of another frame of data. The frames of data responsive to the different elevation apertures are compounded, reducing speckle.
Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.